Fishing hook

ABSTRACT

An improved fishing hook is provided. The fishing hook is made of a wear-resistant material of either: (a) 85% to 96% tungsten carbide and 4% to 15% cobalt, (b) 60% to 89% tungsten carbide, 4% to 28 % tantalum carbide, 4% to 25% titanium carbide and 3% to 30% cobalt, or (c) 34% to 51% cobalt, 25% to 32% chromium, 14% to 21% tungsten, 2% to 4% carbon and one or more of the metals nickel, silicon, columbium, manganese and iron which, together, comprise no more than 16% of the material. For material “b”, preferably the composition contains about 5% to 13% cobalt, 65% to 89% tungsten carbide, titanium carbide and tantalum carbide which, together, are present in an amount no greater than 30% of the composition of the material. For material “c”, preferably the composition contains about 28% to 32% chromium, 43% to 48% cobalt, tungsten and one or more of nickel, silicon, iron, manganese, columbium and carbon which, together, are present in an amount no greater than 29% of the composition of the material.

BACKGROUND OF THE INVENTION

[0001] The invention relates to an improved wear-resistant compositionof materials used for fishing hook construction.

[0002] Conventional fishing hooks are made of one form or another ofmetal. However, the present materials (stainless steel probablyrepresenting the best performing material) are not optimal, at leastwhen compared to the fishing hook of the present invention, as will bedisclosed hereafter.

[0003] Presently available fishing hooks deteriorate (especially whenused in salt water environments, although such does occur in allcontexts) and fail to retain the sharpness of their tips and barbs.

[0004] Heat-treating a fishing hook to form a hard penetrating surfaceswill still produce a hook which will dull very quickly. This, in turn,reduces the frequency of successful catches.

[0005] Objects of the invention include an improved fishing hookexhibiting a penetrating and barb surfaces and tips which are of highhardness, low coefficient of friction and extended service life, andwhich are economically feasible for commercial production.

SUMMARY OF THE INVENTION

[0006] A wear-resistant fishing hook is provided having at leastpenetrating tip and barb surfaces of 85% to 96% tungsten carbide and 15%to 4% cobalt, or, alternatively, a composition comprising 60% to 89%tungsten carbide, 4% to 28% tantalum carbide, 4% to 25% titaniumcarbide, and 3% to 30% cobalt. The fishing hook composition preferablycomprises 65% to 89% tungsten carbide, 5% to 13% cobalt, and titaniumcarbide and tantalum carbide which, together, are present in an amountno greater than 30% of the composition. The fishing hook may be a pairof hand shears, a knife or similar tools. As a second alternative, awear-resistant fishing hook is provided having a cutting edge made of acomposition comprising 34% to 51% cobalt, 25% to 32% chromium, 14% to21% tungsten, 2% to 4% carbon, and one or more of the metals nickel,silicon, columbium, manganese and iron which, together, comprise nogreater than 16% of the composition. This alternative fishing hookcomposition preferably comprises 43% to 48% cobalt, 28% to 32% chromium,tungsten and one or more the metals nickel, silicon, iron, manganese,columbium and carbon which, together, are present in an amount nogreater than 29% of the composition. This alternative fishing hook mayalso be a pair of hand shears, a knife or similar tools.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] An improved fishing hook is provided. The penetrating points andbarbs of the fishing hook are made of a wear-resistant material ofeither: (a) 85% to 96% tungsten carbide and 15% to 4% cobalt, (b) 60% to89% tungsten carbide, 4% to 28% tantalum carbide, 4% to 25% titaniumcarbide and 3% to 30% cobalt, or (c) 4% to 51% cobalt, 25% to 32%chromium, 14% to 21% tungsten, 2% to 4% carbon and one or more of themetals nickel, silicon, columbium, manganese and iron which, together,comprise no more than 16% of the material. For material “b”, preferablythe composition contains about 5% to 13% cobalt, 65% to 89% tungstencarbide, titanium carbide and tantalum carbide which, together, arepresent in an amount no greater than 30% of the composition of thematerial. For material “c”, preferably the composition contains about28% to 32% chromium, 43% to 48% cobalt, tungsten and one or more ofnickel, silicon, iron, manganese, columbium and carbon which, together,are present in an amount no greater than 29% of the composition of thematerial.

[0008] According to the present invention, these materials may beattached to the desired surfaces of an existing fishing hook ofconventional material by cementing or brazing. These materials providehardness and a low coefficient of friction, are typified by the cobalt,chromium, tungsten, tantalum, titanium, and carbon family of materials.While many modifications and additions to these basic components arepossible and appear desirable in a certain range of compositions,certain combinations of carbon, tungsten, titanium and tantalum withcobalt appear to be essential in order to achieve commerciallyacceptable results within the spirit of the present invention.

[0009] The tungsten and carbon alloy presents a hard, wear-resistantsurface and the titanium and tantalum provide a low coefficient offriction. Cobalt is the principal wetting agent in these alloys andbonds these materials to form the required wear-resistant component.

[0010] Other elements in relatively small percentages, such as iron,silicon, nickel and molybdenum, may be included but are incidental tothe manufacture of these alloys.

[0011] A range of compositions has been tested and those combinations,which are in the family known in the art as cemented tungsten carbides,appear to operate well in the present invention.

[0012] Certain tests conducted in related arts indicate certainlimitations relating to the essential metals. For example, it appearsthat compositions including less than approximately 3% cobalt do nothave sufficient strength to prevent chipping or cracking of the metal toform a fishing hook of commercial usefulness. Further, as the percent ofcobalt increases between 6% to about 13%, relatively good strength andwear-resistance is achieved. Also, it is noted that in tungsten carbidecompositions having an increasing cobalt content between 13% and 25%, areduced wear-resistance is found with high-impact strength.

[0013] Expectations are that excellent wear-resistance and strength isachieved in the range of compositions which include 5% to 13% cobalt intungsten carbide compositions.

[0014] In general, compositions of at least approximately 60% to 89%tungsten carbide, 4% to 28% tantalum carbide, 4% to 25% titanium carbideand 3% to 30% cobalt are believed to be optimal.

[0015] In view of the commercially available compositions within thesegeneral limits which heretofore were used for completely differentpurposes, there appears to be no significant advantages to be gained byemploying tungsten carbide compositions containing a cobalt content muchgreater than 13%.

[0016] Fishing hooks made in accordance with this invention exhibitsuperior performance compared to conventional types of hooks.Improvements in such performance criteria as penetrating point and barbpoint wear and high penetration facility. Such improvements are relatedto the fact that the invention provides for better edge strength,wear-resistance and coefficient of friction than has been possiblepreviously in the context of fishing hooks.

[0017] The composition of the present invention has significantadvantages compared to materials used for fishing hook constructionpreviously. For example, the composition can be varied within the scopeof this invention to provide superior wear-resistance or to provide agreater degree of toughness, as required. This is particularlyadvantageous in the critical wear areas of a fishing hook.

[0018] The ease of control of the composition permits a high qualityfishing hook to be manufactured. The strength and durability of thepenetrating surfaces exhibits the desired wear-resistance and toughnessand represents an unexpected and significant advance in fishing hookconstruction.

[0019] In a fishing hook according to the present invention, the mode ofwear is primarily individual particles flattening due to abrasion. Itshould be readily appreciated that, in such a cutting edge, thethousands of particles are being used to their fullest extent becausethe cobalt bonding agent is sufficiently strong to hold the particles inplace and permit maximum utilization of the hard particles.

[0020] All percentages expressed herein are expressed as a weightpercent basis.

[0021] The compositions according to the invention, generally, are madeby conventional methods.

[0022] Cemented tungsten carbide is a product made by powder metalsprocessing. The main stages in the manufacture of this material include:(1) Production of tungsten metal powder; (2) Preparation of tungstencarbide; (3) Preparation of alloyed and other carbides; (4) Addition ofcobalt to produce grade powder; (5) Pressing; (6) Pre-sintering; and (7)Final sintering.

[0023] Tungsten oxide is reduced in hydrogen at a temperature of about2000.degree. F. to form tungsten metal powder which is relatively soft.Carbon or lamp black is added to the tungsten powder and this mixture iscarburized in an induction furnace at approximately 2800.degree. F. toform tungsten carbide powder.

[0024] Cobalt oxide is reduced in hydrogen at approximately 1800.degree.F. to produce cobalt metal powder.

[0025] Titanium oxide and tantalum oxide are mixed with carbon or lampblack and are reduced and carburized in an induction furnace atapproximately 3200.degree. F. to produce titanium or tantalum carbidepowder.

[0026] The above metals are the prime materials used to produce cementedtungsten carbide.

[0027] Selected powders are placed in a ball mill that contains acetoneand is lined with cemented tungsten carbide and employs cementedtungsten carbide balls. The powders are crushed by the grinding actionto produce a powder having a size range of 1-5 micrometers.

[0028] After ball milling for 3-5 days, the powder slurry is placed intrays and thoroughly dried. The powder is then screened and siftedthrough a series of fine metal screens to remove foreign matter and toremove oversize lumps.

[0029] Powders selected to produce a specific grade of cemented carbideare placed in blender and thoroughly mixed to obtain maximum strengthand grade uniformity.

[0030] At this point in the process, the powders are ready for eitherhot pressing or cold pressing to form a final shape. Hot pressing isused primarily for the manufacture of larger carbide parts, and coldpressing is used for a variety of smaller parts.

[0031] In preparation for cold pressing, the dried powder is fed througha hammer mill and wax is added to the powder during the hammer millingoperation. The powder/wax combination is placed in an open-endedtumbling machine and tumbled until small spheres are formed. Thespheres, slightly larger than grains of salt, are then used to fill themold cavity for the cold pressing operation. The purpose of forming thespheres is to allow the mold cavity to fill evenly and equalize thepowder density throughout the mold.

[0032] The pressed blanks are fed through a hydrogen atmosphere furnaceat approximately 2000.degree. F. and the wax is removed from the pressedblank. At this stage, the blanks have the strength of chalk and can bemachined to form required angles or holes, or whatever is required inthe final blank design.

[0033] The blank is placed in a vacuum or hydrogen atmosphere furnaceand heated to approximately 2800.degree. F. and, during this operation,the blanks assume their final size and hardness while shrinking from 20%to 30% of their original volume.

[0034] The hard metal blanks generally have a hardness ranging from 84Rockwell A to 92.8 Rockwell A, depending on the size of the carbideparticles and the percentage of cobalt binder used during the sinteringoperation.

[0035] The blank can be used in the sintered state or it can be machinedby diamond grinding to form a desired surface finish. In order for thesmall carbide blank to be used effectively, it may be attached to alarger or heavier backing material such as a steel shank.

[0036] Techniques for securing the carbide tip or barb blank to a steelfishing hook body include brazing, cementing or by mechanical fastening.

[0037] Brazing is one of the more common methods of securing carbideinserts to steel, and this is readily accomplished by the followingsteps: (1) Clean both mating surfaces; (2) Coat each mating surface withHandy Flux (product of Handy & Harmon Co.); (3) Position brazing shimapproximately 0.003 inch thick between mating surfaces; and (4) Applyheat by hand torch or induction coil.

[0038] The most common brazing alloy used and approved by the AmericanWelding Society is designated BAg3 having a brazing temperature in therange of 1270.degree. F. to 1550.degree. F. with a solidus temperatureof 1170.degree. F. The total braze thickness generally is 0.0015 inch to0.0025 inch which gives a shear strength of 70,000 to 100,000 psi.

[0039] Use of adhesives or cement is another method used to securecarbide to a base material, especially where operating temperature arelow and where bond strength requirements are low. The most commonadhesive is a two-part epoxy resin and these epoxy cements setcompletely in a few minutes at room temperature.

[0040] Hard, cemented tungsten carbide may be machined by severaltechniques. A very common method is by use of a diamond wheel. Excellentsurface finish and sharp edges can be produced on cemented carbide byusing proper wheel selection. Proper wheel selection involves wheeldiameter, diamond mesh size, diamond concentration, bonding material,wheel speed, depth of cut, and use of sufficient coolant or no coolant.

[0041] The 8 to 10 AA surface finish required to produce the sharppenetrating edges and tips of a fishing hook according to this inventionis obtained by rough grinding with a 100-mesh resinoid diamond wheel andfinish ground with a 220-mesh resinoid diamond wheel. To minimize heatbuildup, a flood of coolant must be used during the rough and finishgrinding.

[0042] Depth of cut or down feed using the 100-mesh diamond wheel shouldbe 0.001 inches per cycle until the surface is clean. The final surfacefinish is generated with the 220-mesh diamond wheel using 0.001 inchdepth of cut until the last 5 or 6 cycles when 0.0005 inch depth of cutshould be used to generate the final surface finish of 8 to 10 AA.

[0043] The manufacture of material “a” and “b” has been described in theabove paragraphs. The material classified as “c” is made by melting theingredients in an electric furnace and chill casting in permanent moldsto obtain the required blanks. The hardness of the chilled tip or barbblanks ranges from 62 to 64 Rc. The blanks are attached to a steel hookbody by the same procedure as outlined for brazing of the cementedcarbide blanks.

[0044] The blanks are easily machined by using 100- to 120-mesh aluminumoxide grinding wheels of a soft grade structure. Wheel speeds of 3800 to4200 surface feet per minute and a depth of cut of 0.0015 to 0.0025inches per cycle, along with a flood of coolant, will produce 10 to 12AA surface finish.

[0045] The examples which follow are intended to be illustrative of theinvention but not to limit in any way the scope of the claims below.

EXAMPLE 1

[0046] A material composition was prepared according to the aboveprocedures to produce a composition of 94% tungsten carbide and 6%cobalt. All percentages are by weight unless otherwise indicated. Thespecimens were affixed to fishing hook bodies by brazing and thenfinished by grinding to form the required edges and tips.

EXAMPLE 2

[0047] A material composition was prepared according to the aboveprocedures to produce a composition of the following proportions: 76%tungsten carbide, 12% titanium carbide, 4% tantalum carbide and 8%cobalt. The specimens were affixed to fishing hook bodies by brazing andfinished by grinding to form the required contours.

EXAMPLE 3

[0048] A material composition was prepared according to the proceduresoutlined for material “c” to produce a composition having the followingproportions: 48% cobalt, 31% chromium, 14% tungsten, 2% carbon, 2%columbium, 1% manganese and 2% iron. During the manufacture of thismaterial, the chromium content was converted to chromium carbide whichhas good wear resistance and a low coefficient of friction. The materialwas machined to form fishing hook of highly desirable characteristics.

[0049] While the invention has been disclosed herein in connection withcertain embodiments and detailed descriptions, it will be clear to oneskilled in the art that modifications or variations of such details canbe made without deviating from the gist of this invention, and suchmodifications or variations are considered to be within the scope of theclaims hereinbelow.

What is claimed is:
 1. An improved fishing hook, at least thepenetrating tips and barbs of which are made of a composition consistingessentially of: (a) 60% to 89% tungsten carbide, (b) 4% to 28% tantalumcarbide, (c) 4% to 25% titanium carbide, and (d) 3% to 30% cobalt. 2.The fishing hook of claim 1 wherein said composition consistsessentially of: (a) 65% to 89% tungsten carbide, (b) 5% to 13% cobalt,and (c) titanium carbide and tantalum carbide which, together, arepresent in an amount no greater than 30% of said composition.
 3. Animproved fishing hook, wherein the improvement comprises said fishinghooks having a penetrating tips and barbs made at lead clad of acomposition consisting essentially of: (a) 34% to 51% cobalt, (b) 25% to32% chromium, (c) 14% to 21% tungsten, (d) 2% to 4% carbon, and (e) oneor more of the metals nickel, silicon, columbium, manganese and ironwhich, together, comprise no greater than 16% of said composition. 4.The improved fishing hook of claim 3 wherein said composition consistsessentially of: (a) 43% to 48% cobalt, (b) 28% to 32% chromium, and (c)tungsten and one or more of the metals nickel, silicon, iron, manganese,columbium and carbon which, together, are present in an amount nogreater than 29% of said composition.
 5. An improved fishing hook,wherein the improvement comprises said fishing hooks having at least thepenetrating tips and barbs thereof made of a composition consistingessentially of 85% to 96% tungsten carbide and 15% to 4% cobalt.